Add stratnum GiST support function

This is support function 12 for the GiST AM and translates
"well-known" RT*StrategyNumber values into whatever strategy number is
used by the opclass (since no particular numbers are actually
required).  We will use this to support temporal PRIMARY
KEY/UNIQUE/FOREIGN KEY/FOR PORTION OF functionality.

This commit adds two implementations, one for internal GiST opclasses
(just an identity function) and another for btree_gist opclasses.  It
updates btree_gist from 1.7 to 1.8, adding the support function for
all its opclasses.

Author: Paul A. Jungwirth <[email protected]>
Reviewed-by: Peter Eisentraut <[email protected]>
Reviewed-by: jian he <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com

1 files changed, 7 insertions, 1 deletions

diff --git a/doc/src/sgml/xindex.sgml b/doc/src/sgml/xindex.sgml
index 22d8ad1aac4..3a19dab15e0 100644
--- a/doc/src/sgml/xindex.sgml
+++ b/doc/src/sgml/xindex.sgml
@@ -508,7 +508,7 @@
    </table>
 
   <para>
-   GiST indexes have eleven support functions, six of which are optional,
+   GiST indexes have twelve support functions, seven of which are optional,
    as shown in <xref linkend="xindex-gist-support-table"/>.
    (For more information see <xref linkend="gist"/>.)
   </para>
@@ -590,6 +590,12 @@
         (optional)</entry>
        <entry>11</entry>
       </row>
+      <row>
+       <entry><function>stratnum</function></entry>
+       <entry>translate well-known strategy numbers to ones
+        used by the operator class (optional)</entry>
+       <entry>12</entry>
+      </row>
      </tbody>
     </tgroup>
    </table>